Heat exchangers are, of course, well known in the art and have been used in a wide variety of applications.
One type of heat exchanger, described in European Patent Appl. No. EP 04 019 339.3 (corresponding to U.S. Ser. No. 11/201,783, filed Aug. 11, 2005), is illustrated in FIG. 1, and concerns an exhaust heat exchanger with a bypass 86′. A housing 30′ encompasses the entire periphery of the stack of flat tubes 10′, as is clear by glancing at the figures, with channels 26′ formed by insert parts. The present invention is an improvement upon this heat exchanger, with a simplified design in which a bypass may be included or not. Other components of the FIG. 1 heat exchanger not described here are identified by reference numerals which correspond to reference numbers used to identify generally corresponding components of the below described heat exchangers incorporating the present invention, but with prime (“′”) added to the reference numerals in FIG. 1.